US2449485A

US2449485A - Gas analyzer

Info

Publication number: US2449485A
Application number: US425271A
Authority: US
Inventors: Johnson Clarence
Original assignee: Bailey Meter Co
Current assignee: Elsag Bailey Inc
Priority date: 1942-01-01
Filing date: 1942-01-01
Publication date: 1948-09-14
Anticipated expiration: 1965-09-14

Description

Sept, 14, 1948. c. JOHNSON 2,

GAS ANALYZER Filed Jan. 1, 1942 a sheets-sheet 1 lnvenfor CLARENCE JOHNSON 4 FIG.| My

P 1948- I c. JOHNSON 2,449,485

GAS ANALQYZER Filed Jan. 1, 1942 3 Sheets-Sheet 2 ZSnnentor CLARENCE JOHNSON r (It torneg C. JOHNSON GAS ANALYZER Sept. 14, 1948.

- 3 Sheets-Sheet 3 Filed Jan. 1, 1942 ZSnnentor CLARENCE JOHNSON (Ittomeg FIG. 5

regulator 6, will be discharged through the orifice [2 to the interior of a porous stone vaporizer 13, which rests by gravity as a shroud to the projection of member 8 containing the passage II and the orifice l2,

As clearly evident in Fig. 1, the membera is assembled in the analyzer so that the annulus 9 is aligned with the duct 1 and that the porous stone vaporizer l3, resting by gravity upon the member 8, is retained in a substantially vertical.

position in a mixing chamber l4.

Asa preferred fuel for combustion of th'eifree 4 l2 to the interior of the vaporizer I3, passes therefrom through radial passages 29, through the mixing chamber l4 around the upper portion of the vaporizer l3 and to the exit channel 30. The sample gas contacts the interior and exterior of the vaporizer l3, vaporizing the liquid with which the stone I3 is saturated and thoroughly mixing therewith. I This wiping vaporizing action regulates the vertical height on the porous stone l3 which is saturated or partially saturated with liquid. chamber H! be flooded with liquid fuel and a control of the vertical head of liquid available at the discharge 1 28 regulates the height on the stone 13 which is wet relative to the portion which is substantially dry or wiped free of liquid.

- Inasmuch as the sample gas and the liquid fuel both pass through channels in the heated metallic regulated by ahand adjustment I9 in a passage leading through a filter 20 to a supply pipe 2| leading to the analyzer assembly I. r

The liquid fuel flows by gravity from the pipe 2| toa chamber 22 from the open upper end of a standpipe 23 extension of the pipe 2|. the chamber 22 theliquid rises in a glass sight tube 24 open at its top to the atmosphere :and loosely capped by a dust seal 25. The level in the sight tube 24 is the same asthe liquid level inthefioat chamber Hand remains substantially constant. From the chamber 22 the liquid enters the '.open end'26 of a coil 21 of small capillary Fillin connected at its lower extremity--28 to discharge H thecatalyticelement 32 forms a part, for coninto the mixing chamber adjacent the porous stone vaporizer l3.

The arrangement just described provides a deaerator and liquid fuel rate control. The chamber 22 and the liquid fuel contained therein is uniformly and continuously heated, by means of the heater 3, to a temperature slightly below the vaporization temperature of the liquid but high enough to liberate any air withwhich the liquid maybe saturated. Suchliberated air finds its wayupward through the sight tube 24 to the atmosphere. 7 i I The rate-of supplyof vaporizable liquid fuel through the; discharge 28 (to'the mixing chamber I4) is controlled by a combination of the liquid headvertically betweenthe discharge 28 and the liquid level in the tube 24 andthe flow restricting capillary 21 through which the liquid must pass from the chamber 22 on its way to the discharge a 28. This combination of head and capillaryrestriction is designed to'regulate the rateof liquid flow leaving the exit 28 to a flow rate proportioned to the gas sample entering the mixing chamber through the orifice I2. It is apparent that the length of capillary 21 is fixed when manufactured and that'onlythe head of liquid provides a variable adjustment ofthe rate of liquid flow through the. discharge 28; I may-provide means whereby the. float chamber I'lyis vertically adjustable to, vary the head effective at the point 28 for the calibration of individual analyzers.

Liquid fuel leaves the dischargec28 to thelower. en'cl'of mixing'chamber l4 against and around the porousstone vaporizer l3. Capillary attraction saturatesthe vaporizer l3 for a portion of its vertical-length. The sample gas leaves the orifice block I to a mixing chamber and vaporizer which is also contained in the block I, there will be an equilibrium temperature attained for the sample gas, the liquid fuel and the mixture of gas and.

vaporfuel passing through the exit channel 30 to the analyzer cell. Thesample gas flow and the liquid fuel flow are individually regulated to a uniform rate of flow and in proper proportionality to eachother. 3

The mixture of sample gas and fuel ,vapor passing upwardly through'the exit channel 30 enters a diffuser tube 3| having a plurality of minute openings adjacent the catalytic wire 32 which is suspended from conductor posts 33.. 'The analyzercell is loosely housed by a glass or similar cylinder 34 having an-exit to its top forthe discharge of productsoficomb'ustion from the catalytic burningonthe wire 32. surrounding the cell is a-metallic protection tube 35.

Referring now to Fig. 2; I show thereon in diagrammatic fashion the electrical circuit,- of which tinuously indicating or recording the percentage of. free oxygen or excess air in the sample gas flow. I haveillustrated the analyzer arranged to visually'exhibit by means of a movable index 36. cooperating with. a time revoluble chart 31.

and scale 38. .The index, chart and scale are merely specific forms of exhibiting means which may, take a wide variety of other forms; as will be evident to those skilled in the art. Certain features of the electrical circuit illustrated in connection with the present invention are disclosed andclaimed in thecopending application of John D Ryder, SerialNo. 424,281. now Patent 2,333,393.

Tolprovide j an accurate and sensitive measur-' ing system Ipreferably employ the null or zero balance method wherein a variable effect of measurable value is maintained equal to or in some predetermined proportion to the electrical effect produced by the variable, and hence becomes a measure of the variable; In Fig. 2 I

employ an alternating. current Wheatstone bridge generally indicated at 39 and having as ratioarms the resistance-Maud anadjustable resistance 40. -Theresistance '40, which is moved in, consonance with-the index; 36 by a reversible motor 4l,. is thebalancing resistance Obviously. it is not desired that the may be of considerably greater diameter. While the'greater diameterdictates that more electrical current is necessary to heat the; wire, at the 7 same time I have found that the coil arrangement illustrated-in Fig. 6 amplifies the self-heating of one portion of the wireto another and as aresult the total electrical current necessary to heat the catalyst with no 7 free oxygen being burned thereon is about the same as with the arrangement shown in Fig. 1. The many advantages of rigidity, strength, compactness of structure, and better diffusion of the combustible mixture over the catalyst however indicates that this is a preferred or desirable arrangement. of the catalytic cell construction.

I will now describe more in detail the construction and operation of my improved

pressure regulators

6 and 6A shown in connection with the sample flow inFig. l, in connection with the bias air. sup-ply in Fig. 5, and to enlarged and greater detail in Fig. 3.

Referring in particular to Fig. 3, it will be seen that the fiow regulator 6 comprises preferably ametallic block 49, in which are two longitudinal bores 50 and of approximately one-half inch diameter each. The

bores

50 and 5| are roughly coned at the bottom and open into a short cylindrical passage closed at the lower end by removable screws 52. Positioned in the bores50, 5| respectively are members 53, 54 comprising a long stem with a conical head near the upper end. It is to be noted that the assembly of Fig. 3 is approximately double scale to the construction which I preferably use. The members 53, 54' are shown as resting by gravity against the ends of the screws 52. In this position, and with no flow of gas under pressure entering the conduit 5, the

periphery of the base of the conical section of the member 53 (or the member 54') is adjacent the lower end of a cross slot 55 or a cross slot 56 respectively. These cross slots are milled'across the upper end of the assembly block 49 through the center of the bores 50 and5l. They are preferably of a different width, with the slot 55 being a greater width than the slot 56.

'The gas sample flow arrives at the conduit 5 fromthe cleansing-sampling apparatus at'a pressure which may vary from'say 3 inches of water to 5 pounds gage. This sample flows into the bore 50:below the conical head of the member 53 and the resulting pressure built up in the bore 50 raises themember 53. In doing so a'portion of the slot 55 at either side of the bore 50 is uncovered in varying degree by upward positioning of the conical head of the member 53. This allows a flow of the sample fromthe bore 50; below the conical head, to atmosphere through the two pertions of the slot 55 at opposite 'sides'of the bore 50. Depending uponthe diameter 'of-the conical. head of the member 53' and also uponits total;

weight, as well as upon the width of the slot 55, the rate of flow and pressure of the sampleentering the bore 50 through the pipe 5 willbe decreased by the bleed to atmosphere through the slot 55 until a predetermined pressure is attained within the bore 50 in the space below. the conical headof the member 53. a 4

For best regulation I have found it desirable to have two such assemblies. in series. Thus a passage 51 is provided from the bore 50 to the bore 5| below the conical head of the members 53, 54. The'reduced pressure flow of. the sample is effective through the passageway. .51 to the interior of the bore 5| where it acts in'turn upon the conical head of the member 54, positioning the member 54 vertically relative to the crossslot 56 to a position dependent upon the weight and diameter of the conicalsection of member 54 and upon the width of 'the slot 56. Thus through proper design I am enabled to obtain a static pressure within the bore 5|, and in the outlet duct 1 at a uniform pressure, for example, of 1.6" of water plus or minus .01. This when the pressure available in the conduit 5 varies from 3 inches of water to over 5 pounds gage pressure. I desirably accomplish this in two stages, as illustrated in Fig. 3, and as just described.

The cylindrical heads of the members 53, 54 have approximately .0015 to .0030 inch diameter clearance, or just enough to allow freedom of positioning of the members. In general, the weight design of the members individually is just enough to offset the pressure effective on the conical head of the member times the area of said head, and to result in the uncovering of approximately one-half of the vertical elevation of the

slots

55 or 56. When there is no pressure flow through the assembly 6 the members 53, 54 may rest by gravity upon the ends of the screws 52. The screws 52.

may either or each have a minute axial hole pro-. viding a continuous tiny bleed of air to take to the atmosphere any dirt, moisture, or other foreign material which may be carried into the assembly 5 through the pipe 5. V

It is essential that the pressure .efiective through the conduit'passage 51 be representative only of the static pressure within the bore 50. I have found that if the'conduit 5 enters on approximately the center line of the bore .50 the" mushrooming flow will react to give an erroneous upward force on the conical head of the member- 53. If the conduit 5 enters the bore substantially tangentially to the periphery or Wall of the bore, a vortex is created which adversely affects the vertical positioning of the member 53. 'Furthermore, the centrifugal force of the sample in vortex motion is such that the flow entering the, communicating passage 51 is at a pressure the resultant of the static pressure Within'the 'bore 50 plus an impact or velocity pressure created by the centrifugal motion.

is eliminated. In making this test I remove .the

member 54, plug the bore 5| with a cork, and

attach the duct I to a manometer. By slowly rotating the conduit 5 Ican increase or decrease the pressure efiectiveupon the manometer above and below a predetermined value. With the conduit 5 at the position neutral between such increaseand'decrease I am assured of a measure ment of static pressure within the bore 50 uninfluenced by impact or velocity of flow.

A similar condition exists in connection with the flow through the passage 51 into the bore 5|. Without taking special provision, I would en'- counter a vortex actionand the centrifugal force effect would be added to the static pressure effect" upon the fluid in the duct I. To counteract this By shaping the inlet conduit 5, as shown in detail in Fig. 8, i. e. to

assesseerronenus action I provide a. screw 58 having; a

,beveledinner .end. (referto Flier?) and, which, is adiustedz adjacent. the. opening of the passage 51 into the; bore 51,, The, usual. desirable,- adjust-- ment, is withthe screw 58 assuming a position approximately asshown. in Fig; "7?. In. this:position the impact effect. of the sample entering the bore 51; through the passa e :51: iseliminatedand be und rstoodthat th se. are its way or'ill-ust tion only and that Iam notto be limited thereto necessarily.

What I claim as new and desire to secure-by Letters. Patent. of the United, Stat s is;

Apparatus for supplyinga mixture lofiflsamole; as: and, vaporizedbfuel to a as analyzer of the catalytic combustiontype comprising, in combination, conduit means for supplying liquid fuel,

means conne ted with one end of aidconduit for delive ioeasaidfuelto said conduit under a predetermined head, an extended "length of restricted capillary tubing communicating with the other end of said conduit, a metal block structure containing the capillary, heating means for the block and capillary, a mixing chamber in said block having a porous fuel vaporizing block therein with an extended surface, said capillary communicatin with said mixture chamber, and conduit means communicating with said chamber for delivering sample gas to said vaporizer block.

2. A fuel supply and deaerating system for a gas analyzer comprising the combination with a conduit for supplying a volatile fuel, of means for maintaining a fixed liquid level in a chamber communicating with one end of said conduit, a cylinder wholly below the level maintained by said means, a standpipe extending through the liquid in said cylinder and opening into the liquid therein below the top of the cylinder, means connecting said standpipe to the other end of said conduit, a vent pipe open to the atmosphere and extending upwardly from the top of said cylinder to a point above the fuel level in said chamber, a metal block structure enclosing the cylinder, means to heat the block to raise the temperature of the fuel in the cylinder to near the boiling point to free entrained air, said vent pipe extending beyond the influence of the heated block, and discharge means for said fuel comprising an extended capillary pipe having its entrance adjacent the outlet of said standpipe and extending downwardly through the fuel in the cylinder in heat transferring relation thereto, the resistance to flow of the capillary at the head imposed by said first mentioned means being such as to restrict the fuel delivery to the desired amount and to maintain the level in the vent pipe substantially the same as that in said chamber.

3. In accessory equipment for a gas analyzer in combination, a metal body block in and on which the component parts of the equipment are mounted, heating means for the block, a conduit to deliver liquid fuel for the analyzer, a deaerator chamber within the block containing a standpipe open near the upper end of the chamber and connected at its lower end to the said conduit, the chamber being open to the atmosphere for freeing air liberated from the liquid fuel in the chamber by heat from the metal etl ii q' iue i -iterat c. neste seid c 7130 hit h. aiisiuid: uel vanoriaerlccated in another cham er in said; blotch and a conduit connect- .iu' isaidr aporizer:tosaidchamher outside. of: said combina ion. of c aim; 3.,- wherein the neat drconduit; includes; a liquid fuel flow 1, controlsconeet dzdir ctlyrbetweenitheupper portion ant-he, deaecatonchamber-andthe vaporizer, said "n w control comprising a relatively longasmalihos-ea capillary positioned to, be immersed-in the liquid in said deaerator-chamherl Y 1 5.31:1.accessoruaeuuinm nt f r a g s na y in combination, a metallic mass comprising the support and con-tainer forlthe essential elements o the e uipm nt. therm statica l c nt olled heating means maintaining the mass andtequipment elements at a uniform temperature, a mixing chamber insaid-mass aconduit to deliver liquid fuel into said chamber for the analyzer,

u eatilocated w thin, s l, mas

body member and connected to the liquid fuel conduit, a liquid flow controller within the body member connected between the deaerator and vaporizer, a conduit for conducting sample gas to the mixing chamber adjacent the vaporizer whereby the fuel vapor and sample gas are mixed, and an analyzing cell supported by said body member and connected to said mixing chamber to receive the mixture therefrom.

'1. The combination of claim 6 including a flow controller interposed in the conducting means for the gas sample stream comprising a gas pressure regulator and a measuring orifice between the regulator and the mixing chamber.

8. A catalytic combustion cell for a gas analyzer comprising, a loosely coiled catalytic wire supported with the axis of the coil substantially vertical, a vertical electrical conductor with a laterally offset upper end extension to which one end of the coil is fastened and from which the coil is suspended, and a tube axially located below the center of the coil and to which the lower end of the coil is electrically connected, the tube forming a passage for a combustible mixture to within the catalytic wire coil.

9. Gas analyzing apparatus for continuously determining the percentage of free oxygen in a pressure sample flow of gas comprising, in combination, a catalytic analyzing cell including a heated catalytic wire, a mixing chamber having a conduit leading to said cell, conduit means communicating with said chamber for delivering a vaporizable liquid fuel thereto, means in said chamber to vaporize said fuel, conduit means communicating with said chamber for delivering sample gas thereto, conduit means communicating with said chamber for delivering air thereto to provide an oxygen bias, and common means to regulate the temperature of the materials flowing to and the mixture flowing from said chamber.

10. In a mixing device for the burner of a gas analyzer, a liquid fuel vaporizer comprising an elongated vertically positioned porous stone memher, said member having an axial cavity in its lower end from the upper end of which cavity extend lateral passages to the-exterior of the member, a supporting member for said porous stone having a tube portion normally extending into said cavity, said tube portion provided at the innermost point of projection within the cavity with an orifice restriction, a conduit arranged to deliver vaporizable liquid fuel to the lower exterior of said stone, a conduit for delivering a constant pressure supply of gas sample to be analyzed to the cavity in said stone, and heating means for the assembly.

CLARENCE JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 12 Number Name Date- 1,754,722 Lucke Apr, 15, 1930 "1,825,830 Sullivan Oct. 6, 1931 1,861,877 Quill 4.; 'June 7, 1932 1,969,888 Gibson Aug. 14, 1934 2,015,882 Brewer Oct. 1, 1935 2,023,610 Nettel Dec. 10, 1935 2,122,070 7 Quick June 28, 1938 2,124,074 Mayo July 19, 1938 2,227,899 Grubb Jan. 7, 1941 2,237,558 Hutton Apr. 8, 1941 2,267,722 Ericsson Dec. 30, 1941 2,293,019 Johnson Aug. 11, 1942 2,329,459 Dickey Sept. 14, 1943 2,334,926 Hines et al. Nov. 23, 1943 2,363,478 Boeke Nov. 28, 1944 FOREIGN PATENTS Number Country Date 404,591 1 Great Britain Jan. 18, 1934 r 425,604 Great Britain Mar. 13, 1935 457,777 Great Britain Dec. 4, 1936 OTHER REFERENCES Hablutzel, The Effect of Lead Oxides on the Oxidation of Hexane, thesis in Lib. of Calif. Inst. of Tech. (1933), pp. 17 and'18, and Fig. '4.